プラント機器の劣化予測手法の開発

－電動弁劣化挙動シミュレーション－

抄録

Although a large amount of data (especially in abnormal conditions) is necessary to predict deterioration of nuclear power plant equipment, it is quite difficult to obtain it. For this reason, simulation is expected to be an effective approach to estimate conditions of equipment instead of data acquisition. In this study, we focused on and built a model for a motor operated valve, since the inspection cost is generally expensive due to the number of the valves used in a nuclear power plant. We analyzed the transient of stem thrust in normal and abnormal conditions. Our analytical result successfully reproduced the difference in the stem thrust; if the fluid pressure becomes excessively higher than in normal condition, the stem thrust becomes larger during valve opening.